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45 Late urethral complications after combined HDR brachytherapy and conformal radiotherapy for prostate cancer
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45
46
LATE L'RE'FIrIRAL COMPLICATIONS &.FTER COMBINED HDR BRACHYTHERAPY AND CONFORMAL RADIOTHERAPY FOR PROSTATE CANCER.
DOSE DISTRIBUTION EVALUATION IMPLANTS USING CT-IMAGES
Dingus S. =, W,tu'm IL I. S~schke M. i. Boehmer D. i. Deger S, :. Loening S.A.:. Budach V. i I Dept. of Radiotherapy. 2 Dept. of Urology, CharitY:. Humboldt-University.Berlin. FRG, Introduction: To evaluate the dose-complication relationship for late urethral grade 3/4 reactions a~er HDR interstitial brachytberapy (HDRBT) and external beam radiotherapy (EBRT) for prostate cancer. Material and methods: From April 1993 to September 1997 186 patients with prostate cancer (8 Tic, 48 T2, 86 T3a/b) were treated with two weekly perineal implants of 16 to 24 hollow needles and 9Gy HDR-BT each with Iridium-192 followed by eonformal external beam radiotherapy of 45 to 50.4Gy with high energy photons of a linear accelerator. Mean central urethral doses were analysed and calculated according to the linear-quadratic modell. A stenosis or fibrosis of the urethra were scheduled as grade 3 reaction, a necrosis or fistula were scheduled as grade 4. A dose-complication relationship were generated with a logistic regression (logit plot). Results: With a minimum follow-up of six months (range 6 - 49 months) a total number of 142 patients could be analysed. Median age was 69 years (ranging from 50 to 83 ).ears). 10,5% (15/142) of the patients developed a grade 3 reaction (urethral ~
stenosis or fibrosis), ~.4% respectively.aThe grade Iogit plot "is
,:: i I : ~'~ !=':-=. "~" . . . .
ili
;
li:
: ,~i i i . i shown ia figure I. By ~ ! ? i ~ : ; i : i , i multivariate analysis urethral ~ ,,; i i ; dose ~p=0.035) and , , . . / . , , pretreatment TURP or urethrotomla (p=0.019) w e r e . . . . . . . . . : .. . the strongest predictive ~ = ~ . ~.'~,='- ==,='~,='~=~=~ parameters for development of '--~,",~ a grade 3/4 reaction. Dose Fig.I : NTCP for late grade 3/4 GU reaclions homogeneity within the whole target volume was not significant. The calculated TD5 and TDf0 were 90.9Gy and 159.7Gy. respectively. Conclusions: Central urethral dose should not exceed 91Gy to avoid grade 3/4 reactions. Pretreatmem TURP and urethrotomia enhance the risk of grade 3/4 urethral complications after HDR-BT plus EBRT.
OF
BLADDER
M.J. Steggerda, L M F . Moonen The Netherlands Cancer Institute (Amoni van Leeuwenhoek Huis), Amsterdam, The Netherlands. Introduction: Dose-volume characteristics such as the treated volume ('l-V) and the overdosed volume (ODV), representing the volume receiving at least the reference dosc and twice thc refercncc dose respectively, are often rcported quantitative specifications o f interstitial implants. We investigated, for bladder implants, whether anatomical information from post-implant CT-Lmages should bc used in ordcr to determine realistic dose-volume characteristics of the bladder Materials and methods: tlsually bladder mtplants arc reconstntcled from orthogonal or stereo stmulator radiographs Isadosu patterns arc evaluated with respect to some markers indicating the boundaries of the target volume. DVHs are then calculated of the volume around the implant, without differentiating between bladder and surrounding tissues. The TV and ODV are derived from these DVHs. In order to evaluate whether these volumes are representative for the bladder, post-implant CT-scans have been made of 12 bladder implants. The bladder was delineated on the CT-images and DVHs of the organ were calculated. Thc TV and ODV of the organ and of the volume around the implant were compared. Results: The ratio "IV-implant / TV-bladder ranged from 1.30 to 2.52 with an average of 1.75 (ISD = 0.41). The correlation coefficient of these volumes was 0.80 The ratio ODV-implant / ODV-bladder ranged from I 10 to 2.2l with an average of 1.47 (ISD = 0.34), while the correlation coefficicnt was 0.77. Conclusion: For the 12 investigated cases, on average, the "IV and ODV of the implant extended largely beyond the bladder volume. Moreover, the correlation between TV and ODV of implant versus bladder was rather poor We therefore conclude that specification of dose-volume characteristics of bladder unplants in order to compare implants or to assess complication nsks, requires 3D anatoroacal information from post-implant CT-scans
47
48
BRACHYTHERAPY AS BOOST TREATMENT I N B R E A S T C A N C E R
Preliminary results with new 17G Nucletron°needle m breast c o n s e r v a t i v e braehythcrapy Iridium ~*" boost.
G. Turcato. M.D. , G.B. Pizzi. MD.. Depatment of Radiation Oncology. Mestre Hospital. Venice-Mestre. Italy
Introduction : As part of our department protocol for breast conservative treatment.
interstitial tmplamation was the preferred method of boost, after 50 Gy whole breast irradiation, for "'high risk" patients with microscopic residual or tumour margins < = 2 ram. An analysis of clinical outcome with respecl to local turnout control and breast cosmetic result was performed. Patients a n d methods : between 1993 and 1996.33 patienls received a Brachytherapy (BRT) implant boost and a comparison was drawn from a total experience of 407 treated breasts with External Beam Irradiation (EBI) alone (50 Gy whole breasl followed by a boost of 10 Gy in five fractions to the primary site) in the same period. The median age of the implanted patients was 60.3 years (range 26-85) and the median follow-up was of 27.8 months (range 12-58 months). The implant target volume was determined by physical and clinical examination (pre-excision mammograms, post-operative induration and location of surgical scar or ultrasonography). Local control and cosmetic result were evaluated with respect to histopathology, margin status, extent of surgery and extent of primitive turnout. Geometrical implant quality was assured by use of templates with lateral and vertical separation of the sources of 1.5-1.2 mm. and assessed with a pre-planning dosimetric study designed to maximise the dose homogeneity within a prescription isodose goal of 90 cGy/hr. The prescribed dose was 20 Gy in microscopic residual (10 patients : 30.3 %) and 15 Gy in the other selected cases at risk (23). Numberof sources, plans and length of sources (LDR) or source position ( indexer length ) and number of pulses (PDR) were assigned to encompass the tumour volume with about 2 cm margin. From June 1995 the interstitial BRT is executed with 192 Ir wires in LDR or pulsed dose-rate (PDR) depending on the availability of the PDR micro-Selectron (Nucletron Inlcmational) when is contemporary employed in others BRT treatments. 20 patients underwent PDR and 13 underwent LDR implant boost. The pulse length in PDR implant was 10 minutes per hour with a I Ci =92Iridium source. Results & Conclusion : There were no local failure in BRT boosted patients while I were observed in EBI patients. Cosmetic result was good / excellent in 92 'k of patients which was not significantly different from non-implanted patients. Cosmetic outcomes in BRT is highly dependent from implant accuracy and in particular is important to spare the subcutaneous tissues in correspondence to the edges of the sources.
Burette R.~",Detroux L ~,Hemeleers C ) , V a u d e v i l l e J.~, Vanderick J: V a n D ) c k e ,M), Vanderlinck" A. ~CI.St Jean - Radiotherapy Dpt - IMLEC Centre C o g n i a u x : I 14 rue du MaraJs - tO(K)BRUSSELS DE" 1180 - rue E Cavel132 Since 1997, new thin needles o f 5 french external diameter (17 gauge) were clinical used for patients with T I - 2 N0-1 M 0 breasts cancers treated by Iridium ~ brachy as a boost. All patients had implantation QA control with simulation and TPS calculation (Plato °) with template techniques following Paris-System rules and L D R - M D R remote afterloading management. Physical parameters were collected in order to compare reproducibility of the technique and QA for patient with previous 16-18mm spaced rigid needles QA assurance results show 3,5% mean difference with 16 m m spaced rigid 15(3 Nucletrou ° needles LDR-/vlDR remote afterloading due to f l e x i b i l i t y o f these thinner needles and the absence o f mandrin into the needles during implant. Placement o f a rigid 18 G a u g e m a n & i n enhanced the precision of the procedure. C o m p a t i b i l i t y with H D R remote afterloading has been tested but not yet clinically praticed as with L D R remote afterloading some leak and blockade problems occured when connectors were insufficiently placed in the axis o f the needles. This m i g h t be o f importance for future P D R approach. We noticed a better cosmetic results that m i g h t benefit to the patient. A m i n i m u m o f three years follow up d o e s n ' t seem necessary with respect to previous study on the use o f thin needles which showed better cosmetic results (Baden-Baden ,Venise and York G E C - E S T R O as in Den Haag Nucletron U s e r ' s meetings), C o n c l u s i o n s : cautious use o f new 17G Nucletron needles seems to bring a cosmectic benefit for I r i d i u m ~9: boost with c o m p a t i b i l i t y L D R remote afterloaders. Further studies are needed and PDR H D R clinical use developped.
45
46
LATE L'RE'FIrIRAL COMPLICATIONS &.FTER COMBINED HDR BRACHYTHERAPY AND CONFORMAL RADIOTHERAPY FOR PROSTATE CANCER.
DOSE DISTRIBUTION EVALUATION IMPLANTS USING CT-IMAGES
Dingus S. =, W,tu'm IL I. S~schke M. i. Boehmer D. i. Deger S, :. Loening S.A.:. Budach V. i I Dept. of Radiotherapy. 2 Dept. of Urology, CharitY:. Humboldt-University.Berlin. FRG, Introduction: To evaluate the dose-complication relationship for late urethral grade 3/4 reactions a~er HDR interstitial brachytberapy (HDRBT) and external beam radiotherapy (EBRT) for prostate cancer. Material and methods: From April 1993 to September 1997 186 patients with prostate cancer (8 Tic, 48 T2, 86 T3a/b) were treated with two weekly perineal implants of 16 to 24 hollow needles and 9Gy HDR-BT each with Iridium-192 followed by eonformal external beam radiotherapy of 45 to 50.4Gy with high energy photons of a linear accelerator. Mean central urethral doses were analysed and calculated according to the linear-quadratic modell. A stenosis or fibrosis of the urethra were scheduled as grade 3 reaction, a necrosis or fistula were scheduled as grade 4. A dose-complication relationship were generated with a logistic regression (logit plot). Results: With a minimum follow-up of six months (range 6 - 49 months) a total number of 142 patients could be analysed. Median age was 69 years (ranging from 50 to 83 ).ears). 10,5% (15/142) of the patients developed a grade 3 reaction (urethral ~
stenosis or fibrosis), ~.4% respectively.aThe grade Iogit plot "is
,:: i I : ~'~ !=':-=. "~" . . . .
ili
;
li:
: ,~i i i . i shown ia figure I. By ~ ! ? i ~ : ; i : i , i multivariate analysis urethral ~ ,,; i i ; dose ~p=0.035) and , , . . / . , , pretreatment TURP or urethrotomla (p=0.019) w e r e . . . . . . . . . : .. . the strongest predictive ~ = ~ . ~.'~,='- ==,='~,='~=~=~ parameters for development of '--~,",~ a grade 3/4 reaction. Dose Fig.I : NTCP for late grade 3/4 GU reaclions homogeneity within the whole target volume was not significant. The calculated TD5 and TDf0 were 90.9Gy and 159.7Gy. respectively. Conclusions: Central urethral dose should not exceed 91Gy to avoid grade 3/4 reactions. Pretreatmem TURP and urethrotomia enhance the risk of grade 3/4 urethral complications after HDR-BT plus EBRT.
OF
BLADDER
M.J. Steggerda, L M F . Moonen The Netherlands Cancer Institute (Amoni van Leeuwenhoek Huis), Amsterdam, The Netherlands. Introduction: Dose-volume characteristics such as the treated volume ('l-V) and the overdosed volume (ODV), representing the volume receiving at least the reference dosc and twice thc refercncc dose respectively, are often rcported quantitative specifications o f interstitial implants. We investigated, for bladder implants, whether anatomical information from post-implant CT-Lmages should bc used in ordcr to determine realistic dose-volume characteristics of the bladder Materials and methods: tlsually bladder mtplants arc reconstntcled from orthogonal or stereo stmulator radiographs Isadosu patterns arc evaluated with respect to some markers indicating the boundaries of the target volume. DVHs are then calculated of the volume around the implant, without differentiating between bladder and surrounding tissues. The TV and ODV are derived from these DVHs. In order to evaluate whether these volumes are representative for the bladder, post-implant CT-scans have been made of 12 bladder implants. The bladder was delineated on the CT-images and DVHs of the organ were calculated. Thc TV and ODV of the organ and of the volume around the implant were compared. Results: The ratio "IV-implant / TV-bladder ranged from 1.30 to 2.52 with an average of 1.75 (ISD = 0.41). The correlation coefficient of these volumes was 0.80 The ratio ODV-implant / ODV-bladder ranged from I 10 to 2.2l with an average of 1.47 (ISD = 0.34), while the correlation coefficicnt was 0.77. Conclusion: For the 12 investigated cases, on average, the "IV and ODV of the implant extended largely beyond the bladder volume. Moreover, the correlation between TV and ODV of implant versus bladder was rather poor We therefore conclude that specification of dose-volume characteristics of bladder unplants in order to compare implants or to assess complication nsks, requires 3D anatoroacal information from post-implant CT-scans
47
48
BRACHYTHERAPY AS BOOST TREATMENT I N B R E A S T C A N C E R
Preliminary results with new 17G Nucletron°needle m breast c o n s e r v a t i v e braehythcrapy Iridium ~*" boost.
G. Turcato. M.D. , G.B. Pizzi. MD.. Depatment of Radiation Oncology. Mestre Hospital. Venice-Mestre. Italy
Introduction : As part of our department protocol for breast conservative treatment.
interstitial tmplamation was the preferred method of boost, after 50 Gy whole breast irradiation, for "'high risk" patients with microscopic residual or tumour margins < = 2 ram. An analysis of clinical outcome with respecl to local turnout control and breast cosmetic result was performed. Patients a n d methods : between 1993 and 1996.33 patienls received a Brachytherapy (BRT) implant boost and a comparison was drawn from a total experience of 407 treated breasts with External Beam Irradiation (EBI) alone (50 Gy whole breasl followed by a boost of 10 Gy in five fractions to the primary site) in the same period. The median age of the implanted patients was 60.3 years (range 26-85) and the median follow-up was of 27.8 months (range 12-58 months). The implant target volume was determined by physical and clinical examination (pre-excision mammograms, post-operative induration and location of surgical scar or ultrasonography). Local control and cosmetic result were evaluated with respect to histopathology, margin status, extent of surgery and extent of primitive turnout. Geometrical implant quality was assured by use of templates with lateral and vertical separation of the sources of 1.5-1.2 mm. and assessed with a pre-planning dosimetric study designed to maximise the dose homogeneity within a prescription isodose goal of 90 cGy/hr. The prescribed dose was 20 Gy in microscopic residual (10 patients : 30.3 %) and 15 Gy in the other selected cases at risk (23). Numberof sources, plans and length of sources (LDR) or source position ( indexer length ) and number of pulses (PDR) were assigned to encompass the tumour volume with about 2 cm margin. From June 1995 the interstitial BRT is executed with 192 Ir wires in LDR or pulsed dose-rate (PDR) depending on the availability of the PDR micro-Selectron (Nucletron Inlcmational) when is contemporary employed in others BRT treatments. 20 patients underwent PDR and 13 underwent LDR implant boost. The pulse length in PDR implant was 10 minutes per hour with a I Ci =92Iridium source. Results & Conclusion : There were no local failure in BRT boosted patients while I were observed in EBI patients. Cosmetic result was good / excellent in 92 'k of patients which was not significantly different from non-implanted patients. Cosmetic outcomes in BRT is highly dependent from implant accuracy and in particular is important to spare the subcutaneous tissues in correspondence to the edges of the sources.
Burette R.~",Detroux L ~,Hemeleers C ) , V a u d e v i l l e J.~, Vanderick J: V a n D ) c k e ,M), Vanderlinck" A. ~CI.St Jean - Radiotherapy Dpt - IMLEC Centre C o g n i a u x : I 14 rue du MaraJs - tO(K)BRUSSELS DE" 1180 - rue E Cavel132 Since 1997, new thin needles o f 5 french external diameter (17 gauge) were clinical used for patients with T I - 2 N0-1 M 0 breasts cancers treated by Iridium ~ brachy as a boost. All patients had implantation QA control with simulation and TPS calculation (Plato °) with template techniques following Paris-System rules and L D R - M D R remote afterloading management. Physical parameters were collected in order to compare reproducibility of the technique and QA for patient with previous 16-18mm spaced rigid needles QA assurance results show 3,5% mean difference with 16 m m spaced rigid 15(3 Nucletrou ° needles LDR-/vlDR remote afterloading due to f l e x i b i l i t y o f these thinner needles and the absence o f mandrin into the needles during implant. Placement o f a rigid 18 G a u g e m a n & i n enhanced the precision of the procedure. C o m p a t i b i l i t y with H D R remote afterloading has been tested but not yet clinically praticed as with L D R remote afterloading some leak and blockade problems occured when connectors were insufficiently placed in the axis o f the needles. This m i g h t be o f importance for future P D R approach. We noticed a better cosmetic results that m i g h t benefit to the patient. A m i n i m u m o f three years follow up d o e s n ' t seem necessary with respect to previous study on the use o f thin needles which showed better cosmetic results (Baden-Baden ,Venise and York G E C - E S T R O as in Den Haag Nucletron U s e r ' s meetings), C o n c l u s i o n s : cautious use o f new 17G Nucletron needles seems to bring a cosmectic benefit for I r i d i u m ~9: boost with c o m p a t i b i l i t y L D R remote afterloaders. Further studies are needed and PDR H D R clinical use developped.